//moo.fx.transitions.js - depends on prototype.js or prototype.lite.js + moo.fx.js
//Author: Robert Penner, <http://www.robertpenner.com/easing/>, modified to be used with mootools.
//License: Easing Equations v1.5, (c) 2003 Robert Penner, all rights reserved. Open Source BSD License.
/**
 * @name fx.Transition
 * @class
 */
san.def("fx.Transition", function(san){
	
	/**
	 * 过渡算法
	 * @param {Object} t
	 * @param {Object} b
	 * @param {Object} c
	 * @param {Object} d
	 */
    var Transitions = {
    
        "linear": function(t, b, c, d){
            return c * t / d + b;
        },
        
        "quadIn": function(t, b, c, d){
            return c * (t /= d) * t + b;
        },
        
        "quadOut": function(t, b, c, d){
            return -c * (t /= d) * (t - 2) + b;
        },
        
        "quadInOut": function(t, b, c, d){
            if ((t /= d / 2) < 1) 
                return c / 2 * t * t + b;
            return -c / 2 * ((--t) * (t - 2) - 1) + b;
        },
        
        "cubicIn": function(t, b, c, d){
            return c * (t /= d) * t * t + b;
        },
        
        "cubicOut": function(t, b, c, d){
            return c * ((t = t / d - 1) * t * t + 1) + b;
        },
        
        "cubicInOut": function(t, b, c, d){
            if ((t /= d / 2) < 1) 
                return c / 2 * t * t * t + b;
            return c / 2 * ((t -= 2) * t * t + 2) + b;
        },
        
        "quartIn": function(t, b, c, d){
            return c * (t /= d) * t * t * t + b;
        },
        
        "quartOut": function(t, b, c, d){
            return -c * ((t = t / d - 1) * t * t * t - 1) + b;
        },
        
        "quartInOut": function(t, b, c, d){
            if ((t /= d / 2) < 1) 
                return c / 2 * t * t * t * t + b;
            return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
        },
        
        "quintIn": function(t, b, c, d){
            return c * (t /= d) * t * t * t * t + b;
        },
        
        "quintOut": function(t, b, c, d){
            return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
        },
        
        "quintInOut": function(t, b, c, d){
            if ((t /= d / 2) < 1) 
                return c / 2 * t * t * t * t * t + b;
            return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
        },
        
        "sineIn": function(t, b, c, d){
            return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
        },
        
        "sineOut": function(t, b, c, d){
            return c * Math.sin(t / d * (Math.PI / 2)) + b;
        },
        
        "sineInOut": function(t, b, c, d){
            return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
        },
        
        "expoIn": function(t, b, c, d){
            return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
        },
        
        "expoOut": function(t, b, c, d){
            return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
        },
        
        "expoInOut": function(t, b, c, d){
            if (t == 0) 
                return b;
            if (t == d) 
                return b + c;
            if ((t /= d / 2) < 1) 
                return c / 2 * Math.pow(2, 10 * (t - 1)) + b;
            return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
        },
        
        "circIn": function(t, b, c, d){
            return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
        },
        
        "circOut": function(t, b, c, d){
            return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
        },
        
        "circInOut": function(t, b, c, d){
            if ((t /= d / 2) < 1) 
                return -c / 2 * (Math.sqrt(1 - t * t) - 1) + b;
            return c / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
        },
        
        "elasticIn": function(t, b, c, d, a, p){
            if (t == 0) 
                return b;
            if ((t /= d) == 1) 
                return b + c;
            if (!p) 
                p = d * .3;
            if (!a) 
                a = 1;
            if (a < Math.abs(c)) {
                a = c;
                var s = p / 4;
            }
            else 
                var s = p / (2 * Math.PI) * Math.asin(c / a);
            return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
        },
        
        "elasticOut": function(t, b, c, d, a, p){
            if (t == 0) 
                return b;
            if ((t /= d) == 1) 
                return b + c;
            if (!p) 
                p = d * .3;
            if (!a) 
                a = 1;
            if (a < Math.abs(c)) {
                a = c;
                var s = p / 4;
            }
            else 
                var s = p / (2 * Math.PI) * Math.asin(c / a);
            return a * Math.pow(2, -10 * t) * Math.sin((t * d - s) * (2 * Math.PI) / p) + c + b;
        },
        
        "elasticInOut": function(t, b, c, d, a, p){
            if (t == 0) 
                return b;
            if ((t /= d / 2) == 2) 
                return b + c;
            if (!p) 
                p = d * (.3 * 1.5);
            if (!a) 
                a = 1;
            if (a < Math.abs(c)) {
                a = c;
                var s = p / 4;
            }
            else 
                var s = p / (2 * Math.PI) * Math.asin(c / a);
            if (t < 1) 
                return -.5 * (a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
            return a * Math.pow(2, -10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p) * .5 + c + b;
        },
        
        "backIn": function(t, b, c, d, s){
            if (!s) 
                s = 1.70158;
            return c * (t /= d) * t * ((s + 1) * t - s) + b;
        },
        
        "backOut": function(t, b, c, d, s){
            if (!s) 
                s = 1.70158;
            return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
        },
        
        "backInOut": function(t, b, c, d, s){
            if (!s) 
                s = 1.70158;
            if ((t /= d / 2) < 1) 
                return c / 2 * (t * t * (((s *= (1.525)) + 1) * t - s)) + b;
            return c / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2) + b;
        },
        
        "bounceIn": function(t, b, c, d){
            return c - Transitions.bounceOut(d - t, 0, c, d) + b;
        },
        
        "bounceOut": function(t, b, c, d){
            if ((t /= d) < (1 / 2.75)) {
                return c * (7.5625 * t * t) + b;
            }
            else 
                if (t < (2 / 2.75)) {
                    return c * (7.5625 * (t -= (1.5 / 2.75)) * t + .75) + b;
                }
                else 
                    if (t < (2.5 / 2.75)) {
                        return c * (7.5625 * (t -= (2.25 / 2.75)) * t + .9375) + b;
                    }
                    else {
                        return c * (7.5625 * (t -= (2.625 / 2.75)) * t + .984375) + b;
                    }
        },
        
        "bounceInOut": function(t, b, c, d){
            if (t < d / 2) 
                return Transitions.bounceIn(t * 2, 0, c, d) * .5 + b;
            return Transitions.bounceOut(t * 2 - d, 0, c, d) * .5 + c * .5 + b;
        }
        
    };
	
	return Transitions;
    
});
